The present invention relates to the field of detection of parameters representative of a state associated with a motor vehicle, in particular the glazing of the vehicle, such as a windscreen or a rear window.
Such a state, associated with the glazing, relates to the presence of misting or of drops of water on one face of the glazing, dirtying or else insolation, which are capable of being detected especially by electromagnetic means.
Known detection devices usually include a module equipped with at least one sensor arranged in the passenger compartment of the vehicle, at a distance from the glazing. That being so, such a sensor does not detect a parameter directly representative of a state associated with the glazing, and it is necessary, in the case of a detection by optical means, to provide shades around this sensor in order to prevent stray light being detected. Moreover, such detection can be disturbed by the presence of smoke in the passenger compartment, as may be the case.
Other known devices include a module equipped with at least one sensor fixed, especially by bonding, on one of the faces of the glazing, on the passenger compartment side. It is then necessary, in this case, to provide shades around the sensor, in particular if it is desired to detect a state associated with the other face of the glazing, on the outside.
The present invention aims to improve the situation.
Moreover, the known devices make it possible only to detect rain on the outer surface of the glazing. The object of the present invention is to provide a device making it possible to detect a foreign body on one or other of the faces of the glazing and especially making it possible to detect both the presence of misting and of rain.
To that end the invention proposes a detection device, including a module sensitive to a parameter representative of a state associated with the glazing, consisting of means (E1) for emitting at least one electromagnetic beam (F1) towards one face (AV) of the glazing, means (R) for receiving at least a part of the beam returned by the said face, and of at least one insert (I1, I2) in the thickness e of the glazing, provided with a surface (S1, S2; S11) substantially opposite the said face (AV, AR) and substantially reflecting to the beam (F1), in such a way that the beam, from emission to reception, undergoes a plurality of reflections in the thickness of the glazing, between the surface (S1, S2; S11) of the insert (I1) and the face (AV, AR) of the glazing.
The implanting of an insert is compatible with the present-day techniques for manufacturing glazing of vehicles, especially windscreens and rear windows, which exhibit a heterogeneous structure generally comprising a spacer thickness between two rigid panels. The reflecting faces of this insert make it possible to detect a foreign substance on one or other of the faces of the glazing.
The receiving means are linked to means for measuring a parameter representative of a proportion of part of a returned beam, this proportion being related to a degree of humidity (drops of water and/or misting) and/or to a degree of dirtying (dust) of the face of the glazing.
Advantageously, moreover, the receiving means are configured so as to detect ambient electromagnetic radiation, while the measuring means are able to distinguish this ambient radiation from a beam part returned by the face of the glazing.
The emitting means preferably include at least one emitting source applied against one of the faces of the glazing.
In a variant, a source of this type is implanted into the thickness of the glazing.
The receiving means preferably include at least one sensor for detecting the beam part returned. This sensor is applied against the face of the abovementioned glazing.
In a variant, a sensor of this type is implanted into the thickness of the glazing.
The emitting means are advantageously configured to emit a first beam intended to be at least partly returned by a front face of the glazing, as well as a second beam intended to be at least partly returned by a rear face of the glazing, with a view to detecting foreign substances on the front and/or rear faces of the glazing.
The measuring means are preferably able to distinguish respective electromagnetic radiation arising from the returns from the first and second beams via the front and rear faces.
The module advantageously includes at least one insert equipped with a first reflecting surface opposite the front face, and with a second reflecting surface opposite the rear face, and the receiving means are configured to receive at least parts of the first and second beams, which are reflected respectively by the front and rear faces.
The emitting means preferably include first and second sources suitable for emitting the first and second beams respectively, while the receiving means include a sensor for detecting the reflected parts of the first and second beams; the first and second sources, as well as the sensor, being applied against the same face of the glazing.
According to one advantageous, optional characteristic, the module of the device further includes a temperature sensor inserted into the thickness of the glazing.
Advantageously, the module includes a luminous-flux sensor, especially a solar-flux sensor, inserted into the thickness of the glazing.
The glazing preferably includes a spacer of chosen thickness, and the module includes a part implanted into a thickness of this spacer.
The present invention also envisages vehicle, especially automobile, glazing, including, in its thickness, an insert of a detection device of the abovementioned type, or else an insert at least a part of the surface of which is intended to be used as a reflecting surface of a detection device of the abovementioned type.
Glazing of this type advantageously comprises two substantially transparent panels, which are substantially rigid and separated by a substantially transparent spacer, into which at least a part of the module of the abovementioned device is inserted.
The insert is preferably substantially in contact with at least one of the panels.
Glazing of this type may advantageously form the windscreen of a motor vehicle, or else the rear window of this vehicle.
Other advantages and characteristics of the present invention will emerge on reading the detailed description given below by way of example, and the attached drawings, in which:
FIG. 1 diagrammatically represents a detection device according to the invention including a sensor module at least partly implanted into the thickness of motor-vehicle glazing;
FIG. 2A diagrammatically represents a device for detecting a parameter associated with the state of the glazing, in particular its degree of humidity (droplets of water and misting) on the front and rear faces of this glazing, according to a first embodiment;
FIG. 2B represents a variant of the device represented in FIG. 2A with an insert provided with two reflecting surfaces opposite the respective faces of the glazing;
FIG. 3A diagrammatically represents a detection device according to a second embodiment, with emitting means and receiving means implanted into the thickness of the glazing; and
FIG. 3B represents a variant of the device represented in FIG. 3A with an insert provided with two reflecting surfaces opposite the respective faces of the glazing.